Impact of the Sc3+/In3+ co-substitution on the structural, magnetic, and microwave characteristics of Co0.5Ni0.5Fe2O4 nanospinel ferrites

In this article, In3+ and Sc3+ ions dual-substituted NiCo nanospinel ferrites (ScIn→CoNiFe2O4 NSFs) have been synthesized through citrate-gel auto combustion method to investigate the effect of In3+ and Sc3+ ions on magnetic, and microwave characteristics. The following techniques TEM, SEM, EDX, and XRD were applied to characterize surface morphology, chemical composition, phase identification, and crystallinity of products, respectively. The XRD verified a phase formation of spinel structure with a minor amount of Sc2O3 was observed for products having x ≥ 0.04. The average crystal size (DXRD) of the products was estimated within the 33–68 nm range using the Scherrer equation. SEM and HR-TEM analyses exhibited accumulating sphere-shaped particles. By fitting the room-temperature spectra obtained from Mössbauer spectroscopy (Moss), Hyperfine interactions were determined. The cation distribution shows that there is a migration of In3+ ions in the lattice in an A→B direction with increasing concentrations while the B site is preferred by the larger Sc+3. M−H plots for 300 and 10 K illustrated all products carried out with a ferrimagnetic character. An enhancement in saturation magnetization (Ms) was remarked with Sc–In doping ratio up to 0.04 and thereafter a drop as the Sc–In concentration increased. The tendency in Ms values might be described by correlating it to the cation distribution amongst Oh and Td (octahedral and tetrahedral, respectively) sublattices. Temperature-dependent magnetization measurements were also investigated, which further confirmed the maintenance of the ferrimagnetic character throughout the temperature range 10–300 K. The peculiarities of the microwave properties have been analyzed by the measured S-parameters in the range of 6–18 GHz. It was assumed that the energy losses due to reflection are a combination of electrical and magnetic losses due to polarization processes and magnetization reversal processes in the region of inter-resonant processes. The average value of the reflection coefficient is −14.48 … −14.24 dB. A significant attenuation of the reflected wave energy opens up broad prospects for practical applications as coatings for providing electromagnetic compatibility.